Thermal expansible wire switch device



Dec. 3, 1963 R. R. GICANOV 3,113,192

THERMAL EXPANSIBLE WIRE SWITCH DEVICE Filed Oct. 14, 1960 2 Sheets-Sheet 2 INVHVTOR.

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United States Patent 3,113,192 THERMAL EXPANSIBLE WIRE SWITCH DEVICE Rada Ray Gleaner, 1173 Louis Ave, Windsor, Ontario, Canada Filed Oct. 14, 1960, Ser. No. 62,652 3 Claims. (Cl. 200-413) These and other objects and advantages of the present invention will be fully apparent from the following description when taken in connection with the annexed drawings, in which:

FIGURE 1 is a plan view of the device of the present invention with the cover removed;

FEGURE 2 is a side elevational view of the cover in section;

FIGURE 3 is a view in elevation taken at ninety degrees from the view shown in FIGURE 2;

FIGURE 4 is a view taken on the line 44 of FIG- URE 2; 2

FIGURE 5 is a bottom plan view;

FIGURE 6 is a schematic view of the circuit of the invention, the contacts being shown in open position;

FIGURE 7 is a view similar to FIGURE 6, the contacts being shown in closed position; and

FIGURE 8 is a schematic view showing the device wired into the turn signal circuit of an automotive vehiole.

Referring in greater detail to the drawings in which like numerals indicate like parts throughout the several views, the device of the present invention is designated generally by the reference numeral 10 and it comprises a base 12 having a pair of prongs 14 and 1-6 projecting from the base 1-2.

A dielectric block 18 is carried by the base on the side of the base opposite to the prongs 14 and 16.

A fixed first contact 20 is carried upon one face of an offset L-shaped plate element 22 projecting from'the base 12 and formed integrally with the one prong 14.

A stressed spring element embodying a substantially fiat straight leaf 2 4 is stretched over one face of the block 13 and is provided on its upper end with a right angled extension 2-6 having the free end thereof secured by a fastening element 28 to the upper end of the block 18.

A bowed leaf member 30 is laterally disposed on each side of the central leaf 24. The lower and adjacent ends of the leaf members 30 are formed integrally with the lower free end of the leaf 24. The upper ends of the leaf members 30 extend into notches 32 provided in the upper end of a recess 34 cut in one face of the block 18. The bowed leaf members 30 bias the leaf 24 for M swinging outward movement so that a second contact 36 on the lower end of the leaf 24- cooperatively engages the fixed contact 20.

An L-shaped bracket 38 projects forwardly from the upper end portion of the leaf 24 at the juncture of the leaf 2'4 with its extension 26. The bracket 38 carries an insulating button '40 through which extends an end portion of a thermal wire 42.

The lower end of the wire 42 is anchored in the long leg 44 of an extension 46 projecting upwardly from the "ice base 12 and having its short leg formed integrally with the prong 16.

A resistor 48 has one end connected to the upper end of the thermal wire 42 and has the other end electrically connected to the plate element 22, as shown most clearly in FIGURE 2. A wire 50 has one end connected to the extension 46 and its other end connected to the extension 26 on the upper end of the lea-f 24.

An adjusting screw 52 extends through a hole provided in the free end portion of the extension long leg 44 and has its shank threaded into a boss or nut 54 formed integrally with the base 12, as shown in FIG- URE 2.

in FIGURE 8, it will be seen that the device 10 is in circuit with the turn signal lamps 5S and 60, a switch S6 and the battery 62 of an automotive vehicle. When the switch 56 is turned to either side of its neutral central position, it connects the device 16) in circuit with the battery 62 and one of the lamps 58 or 60.

In FIGURES -6 and 7, the electrical circuit is shown, showing the operation of the device of the present invention. In FIGURE 6, the contact 20, thermal wire 42, and resistor 48 are connected to the prong 14. The other end of the thermal wire 42 is connected to the prong .16. Upon extension of the thermal wire 42 when it becomes heated, the tension on the leaf 24 is relaxed and the contact 36 closes on the contact 20. This shorts the current flow so that the prong 14 is connected by the closed contacts 20 and 36 to the wire 5% and thence to the prong 16.

With resistor 48 out of circuit, the full strength through the current flows to the incandescent bulbs 58 and 60.

When the current ceases to how through the wire 42, it cools off and contracts to apply tension to the leaf 24 and moves the contact 36 away from the contact 20 The resistance value of the resistor 48 is such that when current fiows through the resistor 48 and wire 42, it is not sufiicient to light up the bulbs or lamps 58 and 61 When the wire 50 and leaf 24 short circuit the pron-gs 14 and 16, the current increases to the bulb then causes them to be illuminated.

What is claimed is:

'1. A thermal expansible wire switch device comprising a base, a dielectric block carried by said base, a first fixed contact on said base, a stressed spring element embodying a substantially fiat straight leaf stretched over said block and having one end aflixed to said block, a second contact on said leaf and cooperatively disposed with respect to said fixed contact, a thermal wire connected to said leaf and to said base to relieve the stress in said leaf in response to expansion of said wire and to restore the stress in said leaf in response to contraction of the wire, and a pair of prongs projecting from said base, one of said prongs being electrically connected to said fixed contact and one end of said wire and the other of said prongs being electrically connected to said second contact and the other end of said wire.

2. A thermal expansible wire switch device comprising a base, a dielectric block carried by said base, a first fixed contact on said base, a stressed spring element em.- bodying a substantially flat straight leaf stretched over said block and having one end affixed to said block, a second contact on said leaf and cooperatively disposed with respect to said fixed contact, a thermal wire connected to said leaf and to said base to relieve the stress in said leaf in response to expansion of said wire and to restore the stress in said leaf in response to contraction of the wire, a pair of prongs projecting from said base, one of said prongs being electrically connected to said fixed contact and one end of said wire and the other of said prongs being electrically connected to said second contact and the other end of said wire, and a resistor in series with said wire.

3. A thermal expansible wire switch a base, a dielectric block carried by said base, a first fixed contact on said base, a stressed spring element embodying a substantially flat straight central leaf and a bowed leaf member laterally disposed on each side of said central leaf, said central leaf being stretched over said block and having one end afiixed to said block, the free end of said central leaf being secured to the adjacent one ends of said leaf members, the other adjacent ends of said leaf members abuttingly engaging said block, a second contact on said leaf and cooperatively disposed with respect to said fixed contact, a thermal Wire connected to said leaf and to said base to relieve the stress in said leaf in response to expansion of said Wire and to device comprising restore the stress in said leaf in response to contraction of the wire, and a pair of prongs projecting from said base, one of said prongs being electrically connected to said fixed contact and one end of said wire and the other of said prongs being electrically connected to said second contact and the other end of said wire.

References Cited in the file of this patent UNITED STATES PATENTS 2,299,767 Schmidinger Oct. 27, 1942 2,689,283 Pulvari Sept. 14, 1954 2,820,120 Flatt et a1. Jan. 14, 1958 FOREIGN PATENTS 117,171 Sweden Sept. 10, 1946 Great Britain June 26, 

1. A THERMAL EXPANSIBLE WIRE SWITCH DEVICE COMPRISING A BASE, A DIELECTRIC BLOCK CARRIED BY SAID BASE, A FIRST FIXED CONTACT ON SAID BASE, A STRESSED SPRING ELEMENT EMBODYING A SUBSTANTIALLY FLAT STRAIGHT LEAF STRETCHED OVER SAID BLOCK AND HAVING ONE END AFFIXED TO SAID BLOCK, A SECOND CONTACT ON SAID LEAF AND COOPERATIVELY DISPOSED WITH RESPECT TO SAID FIXED CONTACT, A THERMAL WIRE CONNECTED TO SAID LEAF AND TO SAID BASE TO RELIEVE THE STRESS IN SAID LEAF IN RESPONSE TO EXPANSION OF SAID WIRE AND TO RESTORE THE STRESS IN SAID LEAF IN RESPONSE TO CONTRACTION OF THE WIRE, AND A PAIR OF PRONGS PROJECTING FROM SAID BASE, ONE OF SAID PRONGS BEING ELECTRICALLY CONNECTED TO SAID FIXED CONTACT AND ONE END OF SAID WIRE AND THE OTHER OF SAID PRONGS BEING ELECTRICALLY CONNECTED TO SAID SECOND CONTACT AND THE OTHER END OF SAID WIRE. 